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BELL SYSTEM TECHNICAL JOURNAL 



The corrosion work consists of both corrosion testing and fundamen- 

 tal studies on the mechanism of corrosion processes. The corrosion 

 tests are carried on under normal service conditions and by laboratory- 

 accelerated processes. The results furnish guidance in engineering 

 decisions as to the use of materials. More fundamental investigations 

 in the field of corrosion have to do mainly with the study of the electro- 

 chemistry of corrosion reactions, film formation, etc. It is of impor- 

 tance, for instance, in the development of corrosion theory to determine 



Fig. 5 — Corrosion of lead cable sheath. (1) By direct contact with a pernicious 

 soil. (2) Stray current anodic corrosion. (3) Acetic acid corrosion in fir duct. 



the effect of the environment, and of the passage of small electrical 

 currents, upon the anodic and cathodic behavior of pure metals, and 

 work of this nature is being carried on. 



Underground corrosion is an important part of the field. The most 

 striking examples of this phenomenon are found in steel and iron struc- 

 tures and particularly in the lead sheaths of subterranean cables. 

 Stray currents from trolley systems often cause such corrosion and an 

 elaborate and expensive electrical bonding system is maintained in 

 order to minimize these troubles. The physical and chemical nature of 



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